Co Louth-born entrepreneur and philanthropist George Moore has died in Virginia in the US at the age of 60.
Just last year he was named by Enterprise Ireland as the agency's start-up ambassador to the US.
The successful business man sold his company TargusInfo in 2011 to Neustar for $580 million.
President of the Irish Technology Leadership Group John Hartnett said he was hugely shocked to hear of Mr Moore's passing.
He said he was "probably the most successful technology entrepreneur to come from Ireland" who had given a lot back to the country.
Mr Moore had recently worked with Mr Hartnett and the ITLG to mentor young entrepreneurs, including a recent trip to Co Cork to work with start-ups.
h was also a board member of the Ireland America Economic Advisory Board and the New Ireland Fund and in 2007 he received a honorary CBE for his contribution to the Northern Ireland economy and his international work for all of Ireland.
A UCD graduate, Mr Moore left Ireland in the 1970s after winning a Ford Foundation scholarship.
He went to work in Silicon Valley where he founded National Decision Systems, which became one of the fastest growing companies in the US. He then founded TargusInfo in the 1990s to provide intelligent call processing information for firms ranging from start-ups to established companies, in particular, telecoms providers.
Mr Moore was ranked among the richest on the Sunday Times Rich list and he has donated to Irish many projects in Ireland, including the UCD science building.
He also bought into the crystal and china business through Erne Heritage Holdings, which owns Belleek China and Galway Irish Crystal.
He is survived by his wife and three children.
